This is a request for support of a Gordon Research Conference on Purines, Pyrimidines, and Related Compounds to be held in New Hampshire, summer 1984. There is no other forum which brings together the knowledge of the chemistry of purines, pyrimidines, and related compounds with the advances in detection and characterization of their myriad of biological activities and of related structure-activity and mechanism of action studies. The antimetabolites of this type are used clinically today in the treatment of cancer, autoimmune diseases, a variety of virus infections, parasitic infections, and gout. Members of this class are used as immunosuppressive agents for homografts. Some have shown cardiovascular effects, carcinogenicity, and the ability to inhibit platelet aggregation. Others have roles in cell regulation and even in differentiation, in addition to their classical roles in most co-enzymes and in energy transfer. In the past decade great strides in the understanding of the electronic structures and reactivities of these heterocycles promise that eventually the particular chemical and physical properties of the purines and pyrimidines will be associated with their peculiar versatility in playing roles in such a variety of biological systems. The first Gordon Conference on this subject was held in 1976 at Plymouth State College and was organized by a steering committee consisting of Chairman George B. Brown, John A. Montgomery, Nelson J. Leonard, Robert J. Suhadolnik, and James C. Parham. At that time it was agreed by the Trustees and the steering committee that the conference would be held every five years rather than the usual every year or every other year and that it would be perpetuated by a committee rather than an individual as chairman. The success of the 1981 conference insured the future of this type of conference and the concept of allowing a time interval sufficient for the development of important new discoveries and fields of investigation. However, it was decided that five years should be reduced to at least three years (in this specific area) due to the tremendous response to the last two conferences.